Trim angle indicator



Sept. 11, 3945. CARTER 2,384,452

TRIM ANGLE INDICATOR Filed Oct. 24, 1942 INVENTOR,

LESLIE F. CARTER;

BY WW H IS ATTORNEY.

Patented Sept. 11, 1945 T OFFICE TRIM ANGLE INDICATOR Leslie F. Carter, Leonia,

Gyroscope Company,

4 Claims.

This invention relates generally to artificial horizon indicating instruments.

One of the features of the invention resides in utilization of a trim scale indicator by which the degree of angular adjustment required, between the casing of an instrument of this character and the panel on which it is pivotally mounted, to obtain a true indication from the horizon instrument may be observed.

A further feature of the invention is provided in the novel mechanism employed to adjust the position of the casing about its axis with rela tion to the instrument board panel of the dirigiblecraft on which theartificial horizon indicating instrument is mounted.

Other features and structural details of the invention will be apparent from the following de-' scription when read in relation to the accompanying drawing wherein I Fig. 1 is a front elevation "view'of an artificial N. J 'assignor to Sperry Ina, Brooklyn, N. Y., a corporation of New York Application October 24, 1942, Serial-No; 463,289

horizon instrument constructed in accordance with the present invention.

Fig. 2 is a side elevationview of the instrument shown in Fig. 1, and

Fig. 3 is a detail bottom plan view of the mechanism for adjusting the position of the casing of the instrument with relation to the fixedly mounted instrument board panel.

With reference to the drawing, a conventional type of artificial horizon instrument is employed to illustrate the present inventive concepts. The face of the instrument shownprovides an artiflcialhorizon indication by means of the relatively movable indexes NJ and H. Index ID is an arm which may be positioned by. means of a gyro vertical of suitable construction that is contained within an enclosing casing l2. ,SpacedIinclexes' H are fixed to the casing I2 and, as Well understood in the art, cooperate with the relatively movable index I 11 to give'an indication of level flight when the parts thereof are situated in an aligned relation as shown in Fig. 1. Tilt of the dirigible craft on which the instrument is mounted about the horizontal or pitch axis thereof away from a level flight condition is indicated by departure of the indexes from aligned relation. With tilt about the pitch axes of the craft, the indexes remain in parallel relation and the index H) appears to move either upwardly .or downwardly with relation to the indexes H. If in apparently level flight according to the horizon instrument, the craft is actually either gaining or losing altitude as indicated by an altimeter instrument, it is necessary to trim the horizon instrument to overcome this condition and obinstrument panel l'l.

I end of Which is rotatably mounted in tain a correct-or true indication therefrom. Such conditions necessarily arise-because ofunbalanced loading of the craft or a change-in loading .ofthe craftas it proceeds in flight. The present invention is primarily useful in indicating the degree of trim correction required of the-artificial horizon instrument when the craft isin true level fiight.

The specific instrument shown in Fig.1 is a horizon compass, the stabilized compass --car'd thereof being indicated at 13. The' instrument also indicates tilt about the bank axes or the craft by means of the hereinbefore mentioned indexes l0 and H and also the relatively-movable index I4 and cooperating indexes i 5. The -in ternal construction of the instrument which may include a 'horizonindex positioning and compass stabilizing gyro vertical is of conventional form and is consequently not shown in detail.

In'accordance-with the teaching of the present invention, the outside casing 12 ofthe artificial horizon indicating instrument is pivotally mounted on the instrument board panel of the dir'i'gible craft. As shown in Fig. '2, the instrument boardof the craft is indicated'at l6 and the panel i -'I- of the instrument is fixedly mounted thereon in a suitable manner. Two trunnions 18, one of which is shown inFig. 2,-extend from opposite sides of the casing I2 and journal in two similar bearings I9 which are fixed-to the rear of-"the Panel H has a central opening through which the front or face of-the horizon instrument extends. Bearings 1'9 and trunnions l8 support the casing 12 for pivotal movement about an athwartship-axis with'reference to the craft so that by positioning the casing l2w1'th reference to the panel H, a 'true indication may be obtained from the gyro'controlled horizon instrument.

With particular reference to Figs. '2 and 3,:a novel means is provided for adjusting the angular positionof, the casing 12 and panel I?! in the form of a mechanism which includes an axially rotatable screw threaded rod "'20, one .a boss 2| situated on the side of the casing L2. The rod .20 extendsthrough an opening in the panel I! and the other end is rotatably positioned by a knob 23 with the aid of a plate 22 which .is situated infixed relation .to the front face .of the casing, I2. Knob "23 is secured to the .end of rod 20 and provides turning the same. Rod 20 is mounted for rotation by knob 23 but holds its position between two fixed points on the casing l2 while rotating,

a suitable means for moved either away from or towards the lug 24 as spring 25 flexes to accommodate the motion,

depending on the direction of rotation of the rod. This turns the casing |2 about its pivotal' is turned by means of knob 23, the position and the boss 2| is mounting defined by trunnion l8. and bearings l9 and consequently efiects the relative positioning of the horizon indexes l0 and H previously described in the manner desired.

. This novel structural design for the lower bearing of the casing provides a simple'but flexible positioning mechanismat thebottom of the easing while making possible the use of an ordinary pivotal bearing for the top-bearing of the instrument. This type of structureavoids the necessity for providing a complicated spring-held pivotal bearing at the top of the instrument casing which would be required in the absence ofthe novel construction disclosed by applicant.v Limited but accurate motion of the instrument relative tothe panelboard from which it is suspended is the main object of the applicants construction as herein disclosed. V I The trim scale indicator provided in accordance with the teaching of the invention is shown to include a trim scale plate 3|] which preferably is mounted in a fixed position on the casing l2. A pointer arm orindex 3| movable relative to the scale 30 is controlled bythe described means for varying the angular position of the casing 2 with relation to the panel Arm 3| is moved proportionally to the angular movement of the easing with respect to panel I! accomplished by turning knob 23 by means of a mechanism consisting of fixed sector gear 32 which extends ra dially from the pivotal axis of the casing l2 and is mounted on one of the bearings l9. Arm 3| extends through an opening in the panel 11 to a pivotally mounted sector gear 33 to which it is fixed. The sector gear 33 and consequently arm 3| move about the axis of thegear which is provided. by a suitable bearing on a fixed trunnion extending from the side of the casing l2. The axis ofarm 3| and the aXis. about which the casing moves arev situated in spaced parallel relation. It will be understood that when the casing I2 is moved by the adjusting mechanism through means of knob 23, the pivot axis of the sector gear 33 moves relatively to the fixed, sector 32 and sector gear 33 and arm 3| move correspondingly to change the position of the pointer part of the arm with relation to scale 30. Scale 30 is graduated ,in

angle scale situated on description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. Means for indicating the trim angle of a gyro controlled artificial horizon instrument for dirigible craft comprising the combination of a gyro controlled artificial horizon instrument having a casing adapted 'to be pivotally mounted about an athwartship axis on the instrument board panel of the dirigible craft, a trim angle indicator having a scale extending vertically along the front of said casing, mechanism for varying the angular position of the casing with reference to the panel to compensate for departure in a vertical plane of the fore and aft axis of the craft ,from the normal position required for constant altitude flight, and means cooperative with said vertical scale and responsive to the change in said angular position of said casing for denoting the direction and extent of said vertical departure;

2. An artificial horizon instrument with an outside casing pivotally mountable on the instrument panelboard of a dirigible craft and having a trim the front of the casing, a pointer arm for said scale including a gear sector pivotally mounted on said casing for movement of the pointer arm about an axis parallel to the pivotal aXis of the casing, means for turning said casing about its axis to vary its angular displacement relative to said panelboard, and a second gear sector fixedv to the panelboard concentric with: the pivotal axis of the casing and meshing with said first gear sector to position said pointer 35 arm about its axis and thereby to reflect the angular movement of. said casing upon said trim angle scale.

3. An artificial horizon instrument for diri ible craft having an instrument panelboard, compris- 40 ing a casing mounted on said panelboard for rotation about an axis athwart said craft, said panelboard having an opening therein, mechanism for angularly positioning said casing about said axis with reference to said panelboard, and a trim angle indicator at the front of said casing comprising an arm pivotally mounted on said casing on an axis parallel to the pivot axis of the casing, said arm extending through the opening in said panelboard, means engaging said arm to degrees in the present instance so'that'th'e trim intended that all matter contained in the above position the same about its axis in response to movement of said casing positioning mechanism, cooperative scale and index means supportedmy said arm and said casing respectively to denote the angularity of said casing.

4. Means for indicating the trim angle of 'an artificial horizon instrument for a dirigiblecraft comprising an artificial horizon instrument having a casing pivotally mountable on the instrument panelboard of said craft, a trim angle scale fixed to the front of said casing, mechanismto rotate said casing about its pivotal axis for changing its position relative to said panelboard, a pointer arm for said scale mounted on said casing for pivotal movement about an axis parallel to the pivotal axis of the casing, and a two part engaging mechanism for positioning said arm, one. part of which engaging mechanism is fixed to the arm and the other part of which is fixed to the instrument panelboard. 1

LESLIE F. CARTER. 

